Waymo is so far unproven, but you're right, it may turn up to be a successful product.

I forgot about the Chromecast, that's a good point.

Stadia is close to being new, though there have been similar efforts for some time now. However, it is by no means successful so far, most reviews I have seen from the gaming press have seen it as impressive, but ultimately not a great way of playing games, and Microsoft's offering is likely to quickly outshine it by sheer force of games catalog.